Literature review means to find other articles, books or information about the subject you are researching. One of the purposes is to show that your subject is worthy of researching because others have also researched it. If the subject you are researching is controversial, then it furthermore gives you both sides of the argument and (hopefully) will find more in favor of the side you are defending. It also gives you a place where to begin to write and research your subject.

principle : collection of data about the research topic /project topic from book journal through internet. To foucs what had been done in provious & what can implemnet to betterment of the project /research , to the same we derive suggestion or conclusion . Thanks